mmckenna
I ♥ Ø
I've been using mostly Larsen antennas for 30 years. I'm happy with them, they do the trick.
But, I like to keep my mind open and look for other options, and at least give them a try. I've been considering the EM Wave antennas for a while now. I like their all black look, their elastomer spring, and the way they seal at the base. I almost purchased one of their sample packages late last year, but it had some antennas I wouldn't use. So, I finally purchased two of their VHF quarter wave whips to try out.
Testing was done with an Agilent N9342C spectrum analyzer with tracking generator and an HP 86205A directional bridge. Cables for the test were Times Microwave phase stable with N connectors all the way through.
Test platform is a 2018 Ford F-350 crew cab with a Larsen NMO-HF mount pretty much dead center on the roof. Truck was about 50 feet from the closest anything, and all 4 doors were closed. No, not an RF test range, but good enough for what I' doing.
——Disclaimer——
EM Wave EM-M10001-LS is a no spring quarter wave. I have it cut for the VHF band. It gets used for 2 meters as well as some VHF stuff at work.
So, no issues staying below an SWR of 2.0:1 across the VHF ham and LMR band. It would be easy to trim it a bit and improve performance higher up, but I don't do any transmitting above about 159MHz. This antenna will live on my wife's 2021 Chevrolet Colorado crew cab, like the Ford, Larsen NMO-HF mount in the center of the roof. Nice thing is that the all black antenna looks better than chrome on a dark red truck.
EM Wave EMFLX-M10001 is a quarter wave with a spring base. This one is cut a bit higher since I use it on my own personal truck and it gets used up around 154 and 156 a bit more than on the ham bands. Exact same test setup/vehicle as above.
On my truck, having the spring base is an advantage since the roof of the truck is around 7 feet high.
Again, easy to keep this antenna at 2.0:1 SWR across the entire VHF ham/LMR band with some room to spare. I think the larger diameter spring at the base improves the antenna bandwidth compared to the non-spring antenna. Comparing this antenna and the EM-M10001-LS, they have the same diameter whip.
And, yes, as I've pointed out before, a VHF quarter wave performs pretty well (when looking at SWR) on the UHF band:
Here's the UHF sweep for the EM-M10001-LS
And here's the UHF sweep for the EM Wave EMFLX-M10001
But, I like to keep my mind open and look for other options, and at least give them a try. I've been considering the EM Wave antennas for a while now. I like their all black look, their elastomer spring, and the way they seal at the base. I almost purchased one of their sample packages late last year, but it had some antennas I wouldn't use. So, I finally purchased two of their VHF quarter wave whips to try out.
Testing was done with an Agilent N9342C spectrum analyzer with tracking generator and an HP 86205A directional bridge. Cables for the test were Times Microwave phase stable with N connectors all the way through.
Test platform is a 2018 Ford F-350 crew cab with a Larsen NMO-HF mount pretty much dead center on the roof. Truck was about 50 feet from the closest anything, and all 4 doors were closed. No, not an RF test range, but good enough for what I' doing.
——Disclaimer——
Yes, ThANk yOU Einstein, I know SWR is NOT the only measure of an antennas performance. Yes, I've swept 50Ω dummy loads and they look great on the screen. This is simply for discussion. An antenna range with a turn table large enough to hold a long bed/crew cab F-350 and doing field strength tests would be wonderful, but I don't currently have access to one. If you do and you want to try it out, I'm happy to oblige. For simplicity and because this website is geared towards hobbyists, I've set the analyzer to show SWR. Yes, it'll do return loss, but I'm not going to rerun all the tests so you can geek out on that. Get your own antenna analyzer.
—— Disclaimer —— EM Wave EM-M10001-LS is a no spring quarter wave. I have it cut for the VHF band. It gets used for 2 meters as well as some VHF stuff at work.
So, no issues staying below an SWR of 2.0:1 across the VHF ham and LMR band. It would be easy to trim it a bit and improve performance higher up, but I don't do any transmitting above about 159MHz. This antenna will live on my wife's 2021 Chevrolet Colorado crew cab, like the Ford, Larsen NMO-HF mount in the center of the roof. Nice thing is that the all black antenna looks better than chrome on a dark red truck.
EM Wave EMFLX-M10001 is a quarter wave with a spring base. This one is cut a bit higher since I use it on my own personal truck and it gets used up around 154 and 156 a bit more than on the ham bands. Exact same test setup/vehicle as above.
On my truck, having the spring base is an advantage since the roof of the truck is around 7 feet high.
Again, easy to keep this antenna at 2.0:1 SWR across the entire VHF ham/LMR band with some room to spare. I think the larger diameter spring at the base improves the antenna bandwidth compared to the non-spring antenna. Comparing this antenna and the EM-M10001-LS, they have the same diameter whip.
And, yes, as I've pointed out before, a VHF quarter wave performs pretty well (when looking at SWR) on the UHF band:
Here's the UHF sweep for the EM-M10001-LS
And here's the UHF sweep for the EM Wave EMFLX-M10001
